The studies were made using cyclic voltammetry on a glassy carbon electrode in aqueous solution containing phosphate buffer solution as supporting electrolyte. The purpose of the investigation was to carry out a quantitative detailed study of the electrochemical oxidation of catechol in the presence of 4, 4-bipyridine in aqueous solution. The electrooxidation of catechol produces a very reactive intermediate, o-benzoquinone, which subsequently reacts with 4, 4-bipyridine in 1, 4-Michael addition reaction to form the corresponding catechol derivative product. The kinetic data were extracted from cyclic voltammograms with the help of digital simulation. The results of the study show that catechol is oxidized in aqueous phosphate buffer solution to a very reactive intermediate o-benzoquinone.